Here is the circuit diagram of a battery eliminator circuit that can be used as a replacement for 9V PP3 batteries. The circuit given here can be used to power any device that operates from a 9V battery. The transformer T1 steps down the mains voltage and bridge D1 performs the job of rectification. Capacitor C1 is a filter. IC LM317T is the regulator here. The value of R1, R2 and R3 are so selected that the output voltage of IC1 will be steady 9 volts.

Circuit diagram.

Notes.

Assemble the circuit on a good quality PCB.

Transformer T1 can be a 230V primary, 9V secondary, 1.5A step down transformer.

If 1A Bridge is not available, then make one using four 1N 4007 diodes.

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Comments

Rod. Oliveros

November 14, 2014

Sir, do you have a simple electronic circuit diagram for (NVH) Noise Vibration Harness tools? i.e noise catcher,noise analyzer or similar. that i might be use for diagnoses of squeaking, rattling and knocking?

Dear Sir , i need help by asking , have car stero battery eliminator 6 amp ,12amp ,,,,can i charge a car battery with it ? if yes how ?
2. i have a desktop computer UPS 600VA microtek, can i charge my car battery with it ? if yes how ?
car battery specification is 12V , 35 AH
pls reply my query, i shall be very thankful for the reply .

Hi Anish you can use a rotary switch to have step variation. if you want a continuously variable power supply. replace R1 and R3 combination with a variable rheostat (a potentiometer connect one end to center tap, hence only two connection used as a variable resistance) of value 2.5K connected with 3K in parallel. The output will be variable between 1.25 to 9 volts. please go through datasheet of national semiconductors.http://www.national.com/ds/LM/LM117.pdf

Hi Anish PP3 is 9volt energizer pack – layer battery with snap on connectors, used in most digital multimeters.
R2 is 220 ohms for 1.25 volt reference. R1 in parallel with R3 to be calculated each voltage. [(Voltage out put required – 1.25 Volt) / 1.25] X 220. For 3 volt it should be 308 ohms, For 4.5 572 ohms. for six volts 836 ohms, for 9 volt 1364 ohms. These are values if ref is 1.25volt. due to its tolerance you may have little variation in the value. Use nearby preferred values for these resistances. 300, 560, 820, 2nos 2.7K in parallel. etc